I have switched this blog's commenting system from a basic open source plug-in to Disqus. I feel ambivalent for outsourcing my data to third party services. But hosting my own comment system takes maintenance. Disqus also has nicer UI and more features like email notification. Let's hope the Disqus service will remain available for a long time.
Incidentally while I'm working in the Disqus integration, Facebook has rolled out their own commenting web services. Facebook is becoming the new Microsoft. I'll rather support competitions.